Injection syringe



Jan. 18, 1955 INJECTION SYRINGE Filed May 2, 1952 17 4 -31 i/o-Yflavgi Y 4 INVENTOR.

.1. VOORHORST 2,699,777-

United States Patent INJECTION SYRINGE Johan Voorhorst, The Hague, Netherlands Application May 2, 1952, Serial No. 285,620 2 Claims. (Cl. 128-215) Recent investigations have shown that in the use of an injection syringe, more particularly when adminstering injections to a great number of living beings, a great danger of infection resides.

This invention is based on the recognition that this danger of infection is due to the circumference that when administering injections to a number of living beings with the same injection syringe but while each time interchanging the injection needle once used for a sterile needle, some infectious fluid will stick to the point of the used needle after an injection has been administered to an infectious being and this fluid, together with the injection liquid still contained in this needle, will be sucked back and will contaminate the inner wall of the injection syringe or the remainder of the injection fluid still contained in the syringe, when the used injection needle is taken off the injection syringe.

When a subsequent injection is administered with the same syringe the patient in question may be infected, notwithstanding the fact that a fresh and naturally sterile needle is used, because the syringe or the liquid to be injected itself has been contaminated.

The object of this invention is to avoid the danger of ection resulting from the administration of injections, by providing an improved injection syringe.

To that end the injection syringe according to the invention comprises an air-inlet opening adapted to be obturated, said air-inlet opening being provided in the interfitting connecting nipples of the reservoir of the injection syringe and of the injection needle.

Said connecting nipples of the reservoir of the injection syringe and of the injection needle can be provided with coupling means which only admit of being decoupled when the air-inlet opening is in its open position.

In illustration of the invention an embodiment of the injection syringe will be described with reference to the accompanying drawing.

According to this drawing the nipple 1 of the injection syringe 2, which syringe may be of a conventional construction, is provided with a bore 4 ending in the central nipple passage 3. The injection needle 5 is provided with a nipple 6, the internal bore of which fits on the nipple 1 of the syringe and provides an air and liquid tight seal therewith, the outward configuration of said syringe nipple corresponding to the shape of the inner bore of the needle nipple. In the needle nipple 6 a slot 7 is provided.

For the purpose of sucking in injection fluid and for administering an injection the needle nipple 6 is so placed on the syringe nipple 1 that the bore 4 in the syringe nipple 1 is kept closed by the solid portion of the needle nipple 6. After the injection fluid has been sucked into the barrel of the syringe and has been injected by pressing down the piston movable in said barrel, the needle nipple 6-before the injection needle is removed from the syringe-is turned about its axis so far that the slot 7 provided in the needle nipple 6 will lie opposite the bore 4 in the syringe nipple 1. When in this relative position of the needle and syringe nipples the injection needle is taken off the syringe, there will be no tendency at a vac-- uum forming in the space between the syringe nipple and the needle nipple which are being removed from each other, because of the atmospheric air immediately enter ing via the slot 7 and the bore 4, so that the danger of infectious fluid being sucked back together with the contents of the injection needle 5 and of the syringe nipple 1 or the fluid still present in the central passage 3 of said nipple being contaminated, is avoided.

When a fresh sterile needle is placed on the injection syringe it is practically certain that the fresh injection fluid to be sucked up is not contaminated by its being mixed with a contaminated remainder of previously used injection fluid or by its contacting a contaminated portion of the syringe.

Meanwhile it will be cleard that the slot 7 provided in the needle nipple can be replaced by an opening extending transversely through the wall of the nipple or by a groove provided in the inner wall of said nipple and extending to the free edge of the nipple. The bore 4 in the syringe nipple 1 can also be replaced by a groove provided in the outer wall of said nipple and extending to the free edge of the nipple.

I claim:

1. An injection syringe having a nipple at the lower end thereof, an axial bore extending through said nipple, an injection needle having an axial bore therein and a nipple at one end thereof, means for interconnecting the two nipples with the two axial bores in uninterrupted alinement, and an opening in each of the two nipples, said openings adapted to overlie each other in one position of the nipples and adapted to be closed oft from each other in another position of the nipples.

2. An injection syringe as defined in claim 1, said opening in the injection needle nipple being in the form of a slot extending to the edge of the nipple.

References Cited in the file of this patent UNITED STATES PATENTS 1,596,004 De Bengoa Aug. 17, 1926 1,831,668 Juhl Nov. 10, 1931 2,032,723 Schweser Mar. 3, 1936 

